This invention relates to method and apparatus for altering the rigidity of fabrics and other web-like materials.
It is desirable to improve the softness, hand, drape aesthetic characteristics, and reduce the material bending stiffness of fabrics or the like without deleteriously affecting other properties thereof. Unfortunately, most of the existing equipment in the textile and nonwoven industry exerts physical pressure on the material in process. As a result, the treated material may have increased density and/or reduced loft in conjunction with any softening or improved drape that may result. Moreover, existing methods for softening fabrics usually undesirable reduce fabric surface integrity due to physical contact of the processing equipment with the fabric surfaces.
Several prior art patents relate to drying, fixing, setting or reducing a treated or coated web of textile material without injury to the web or to the applied treatment by air-conveying the material over the necessary distance without frictional support or any physical contact that would tend to injure the web or the applied treatment. For example, U.S. Pat. No. 3,662,476 to Capizzi discloses an apparatus for drying web from printing devices wherein a plurality of nozzles on one side of the web are staggered relative to a plurality of nozzles on the opposite side of the web which leads to the formation of waves in the web as it moves through the apparatus. The web enters a housing through an inlet and exists through an outlet. The nozzles are provided with extensions defining air discharge openings whereby streams of air can be applied to the web by means of the extensions. The air streams develop at least some flow which is transverse to the direction of the web movement, however, which transverse flow tends to disrupt the flow of air longitudinally in the direction of air movement, thereby reducing the tendency for air to move out of the dryer, reducing the demand on the exhaust means and reducing the inflow of atmospheric air through the inlet and outlet openings. The air streams do not exist through the outlet, do not carry the web from the inlet to the outlet, and do not control the feed of the web.
In U.S. Pat. No. 3,287,821 to Schregenberger, a web is supported by a plurality of air jet streams in registration on opposed walls of the air-conveying apparatus. The air jet streams are positioned at points which occur at intervals which minimize undulation or possible vibration that may injure the web material or a surface applied treatment. The air is substantially recovered and reused. Rather than entering and exiting the apparatus at locations where the web enters and exits, each air jet stream air is in the form of an undulating air stream, and the incidence of web impingement is based on the number of air inlets and outlets that are present. The web itself does not undergo oscillation.
In U.S. Pat. No. 1,847,915 to Bailey, a coated web is dried by passing the web between a pair of air streams which alternately approach and leave the surfaces of the web due to alternate contractions and expansions of the duct through which the air flows. However, the contractions and expansions are not staggered, and the web does not oscillate.